LTRDump Program  10-Nov-2004 Beta Version
LTRTrunk Version 3.84 beta ec4

These programs are proof-of-concept versions to test
various aspects of LTR decoding.  Eventually it will
be part of the Trunker/Etrunk programs.

LTRDump.exe will decode and display LTR information. It also
logs the data to a log file named ltrdump.txt in the same
directory as the program.

LTRTrunk.exe will track regular LTR, LTR-Net, Multi-Net LTR,
and Passport systems. Most of the Trunker features
like talkgoup and id tagging may even work.

These programs run in DOS and have similar requirements
to eTrunk, the EDACS trunk program.  LTRDump.exe is based on
the eedump.exe program version 3.8.3.  LTRTrunk.exe is
based on the etrunk program version 3.8.3.

You will need a slicer with a low pass filter to eliminate
voice frequencies.  Slicer point "A" on the BC780 can be used
if you start the scanner in trunk mode scanning a LTR bank.
http://209.145.176.7/~090/awh/bc-780xlt.html#disctap
I find that slicer point "A" does work when not trunk mode
if you start it in trunk mode on a LTR bank.

Some other data slicers are at
http://home.hvc.rr.com/bpetrow/

Setup of the program is similar to Trunker/Etrunk.  You
need to make a trunker configuration file.  There are no
adjustments in the ltrdump program so the configuration
file is need.  When using the slicer point "A" on
my BC780 I have to set TRACKSLICERMODE to INVERT.

It is best to set the receiver feeding the data slicer to
the status channel.  The status channel sends complete system
information very much like a control channel in a Motorola
or EDACS trunked system.  Because the data is sent in a subaudible
form, the status channel may sound like a silent carrier.
After getting the programs working scan around the bands for LTR
signals, you may be surprised.

If the LTR system does not have status channel then it can
be more difficult to monitor the complete system if multiple
home channels are used.  Setting the receiver feeding the data
slicer to a home channel frequency will allow tracking of any
groups having that frequency as the home channel.  When no
transmission is occuring the ltrtrunk program will display
the sig?inv error at the top right of the screen.  There is
also a tendency for the program to decode noise as valid LTR
data so groups with low usage counts may not be valid.

If you monitor a LTR-Net or Multi-Net status channel with LTRDump
be aware that the ltrdump.txt file can get up into the megabytes
after 30 minutes or so.

Multi-Net frequencies are calculated similarly to Motorola trunked
systems.  The default plan is 8.  Change to 9 for 900 MHz or 0 for
others.  Regular LTR uses plan 0.  Passport uses a similar system
as Multi-Net and only some of the calculations are done.  Passport
uses plans A through P. A map file can be used for Passport frequency
determination if the built-in plan calculation is missing or wrong.  
The most common mapping is for the 450 to 470 MHz range.  To override
the built-in mapping change the plan to 0 and manually edit the
frequencies in the xxxxSYS.TXT file, where xxxx is the system ID in
4 digit hex.

A map file can be used for any system with a plan of 0.  The name
of the file is xxxxMAP.TXT, where xxxx is the system ID in 4 digit
hex.  The base, step, and channel/repeater number (LCN) in hex are
entered in ascending channel number (LCN) order.  For a Regular LTR
system the lines in the file would look like this:
451.5,0.0,1
454.2375,0.0,9
453.750,0.0,b
which will specify that channel 1 is 451.5, channel 9 is 454.2375
and channel 11 (b hex) is 453.750.  The step has to be zero.

Passport uses a frequency map.  For example the map for a Passport
system in the 450 MHz range would require the following line in the
xxxxMAP.TXT file:
450.0125,0.0125,1
this specifies LCN 1 has a frequency of 450.0125 and steps 12.5 KHz
for each increment of LCN.

If you find a system using a band that is not defined or is not
mapping the frequencies properly let me know about it.  It appears
the band can be determined from received data but not enough systems
have been monitored to get complete information.

Screen Layout - LTRDump

 The bottom left part of the screen displays unknown messages or
 extended messages.

 The right side of the screen is used for system information.
 The type of LTR system, Area, and Multi-Net infomation will be
 displayed. The type can be "Regular LTR" for regular and some
 extended LTR, "LTR-Net LTR" for LTR-NET, "Multinet LTR" for Multi-Net
 and "Passport LTR" for passport LTR.  "Burst" is added if only one
 or two packets occur during a transmission.

 The upper left side of the screen displays the frequency and group
 information.  The Free channels are displayed so you can get a idea
 of the channels in the system.

Changes since the last release (beta ec3)

 More changes to improve the program.  The majority of the work
 was done to LTRDump this release.

 LTRDump

  Passport check is done!  The last bits are determined (hopefully).

  For Multi-Net and Passport the radio ID (if available) is displayed
  to the right of the talkgroup prefixed by a RID: label.

  Added frequency calculation to Passport only.  No all bands are
  supported and some bands may be improperly calculated.  The
  frequency is displayed to the right of the talkgroup/RID info.

  Change the log file format.  Frequencies will be used if available.
  The Passport neighbor message has a new format:
  DCC:0 450MHz N:1 S:70  RI Nbr-> 450MHz N:1 U 463.88750
  The left section, before the "Nbr->" gives the site information
  showing the band, network id, site id, etc.  The right side gives
  the neighbor information showing the band, network id, and
  frequency (or LCN).  The example shows this site is on the 450 MHz
  Band with a network id of 1 and site number of 70.  The "R"
  indicates this is a registration frequency.  The "I" indicates an
  idle channel and is replaced with a "B" if the channel is busy.
  The neighboring site is also on the 450 MHz band with a network id
  of 1 and a frequency of 463.8875.  The U is for a bit with an
  unknown purpose.  If None appears instead of a frequency or LCN
  then the site either has no neighbors or no neighbor information
  was defined.  I noticed some sites will only send neighbor
  frequencies on some of the site frequencies.

  Minor fixes 

 LTRTrunk

  Passport check is done!  The last bits are determined (hopefully).

  Added frequency calculation to Passport only.  No all bands are
  supported and some bands may be improperly calculated.  Use plan
  0 to override.

  The Affilate and Neighbor information logging works.  It will
  also show frequencies.  A Affilate message showing the home
  channel assignment is added.
  Minor fixes

Known Problems - LTRDump

 Decoding of information is very basic.  The automatic LTR type
 detection really only works on transmissions and not on bursts.

 LTR-Net detection only works on a idle system.
 
 ESAS is not detected or decoded.

 Multi-Net and Passport frequency display is done modulus 31 so it
 is possible for frequency information to be displayed on top of
 other frequency information.

Known Problems - LTRTrunk

 Decoding of information is very basic.  It will decode Regular LTR,
 Multi-Net, and Passport. CW-ID and extended commands may show up as
 a talkgroup.

 The system id (site id) of a passport group id is not used.  This may
 cause a local group to be merged with one or more different groups
 from another site.  The mobile unit id is not used.

 Sometimes the system id will come up as 0000 or 0001 instead of
 the site number based system id.  Restarting the program usually
 fixes it.

 If multiple systems share a frequency or errors occur then the
 system type can change and collected information can be lost.

 No filtering of Regular LTR and Passport packets to reduce noise
 being decoded as valid data.  This will be looked at more as basic
 decoding progresses.

73 Eric